This disclosure relates to a device for testing batteries. In particular, this disclosure relates to a battery tester for testing power tool batteries.
Cordless power tools generally use batteries that are rated at 9.6 volts, 14.4 volts, 18 volts, or 24 volts. Often, a user may have several batteries that can fit or be used with the same power tool. When the user has several batteries in the field, it is helpful to be able to determine which of the batteries are charged, and to what degree.
Battery testers exist in various forms. Analog and/or digital voltmeters (DVMs) typically have two long wires or leads with metal probes at each end. The user touches the probes to an electrical source, such as a battery or battery terminals, to measure the battery voltage. Based on the user's analysis of the measured battery voltage relative to the maximum expected battery voltage, the user may infer the amount of remaining battery life.
However, this process is physically cumbersome because the user must maneuver the probes to make electrical contact, while at the same time adjusting the knobs on the meter. This is certainly not a one-handed operation. In some circumstances, two people may be needed to perform the task. While this may provide an indication of the actual voltage level, some level of technical sophistication is required to determine the meaning of the measured voltage. For example, if a fully charged battery has a voltage of 14.2 volts, what does a measured voltage level of 10 volts mean? The user must be able to correlate the measured voltage relative to the maximum expected voltage and arrive at a value representing the remaining battery life.
Some battery testers are in the form of a box with a plurality of slots or cradles. The slots are configured to receive small batteries, such as D-cell batteries, C-cell batteries, AA-cell batteries, and AAA-cell batteries. The battery is placed in the slot between two metal contacts, and a meter or display provides an indication whether the battery is good, bad, or somewhere in between. However, such testing boxes are relatively large and cumbersome, and are not adapted to testing power tool batteries. It is often difficult to remove the battery from the slot once inserted.
Accordingly, a battery tester for a power tool battery is needed that provides the user with an indication of remaining battery life, and which can easily and conveniently engage and disengage the power tool battery.